miércoles, 2 de marzo de 2011
EXERCISES ABOUT WOOD
Materials for Technical Use: Wood
Wood Exercises
1 ESO technology wood Unit
jueves, 3 de febrero de 2011
Properties of Materials
1-Physical Properties
Electrical Conductivity: When electricity can run though the material.
Examples:
Steel is a good conductor
Wood isn't a good conductor
Optical properties:
How materials behave when light touches them
Them can be classified into:
a) Opaque: No light travels through them. e.g wood
b) Transparent: All light travels through them and you can see what's behind the materials. e.g glass of window
c) Translucent: All light can travel through them but you cannot see what's behind them e.g frosted glass
Thermal Conductivity
¿ What is conductor and what is insulator ?
Plastic handles are ...
Metal Body is ...
Thermal conductivity is the ability of the material to conduct heat. e.g. Saucepan. Metal body for thermal conductivity and plastic handles for thermal insulation.
Thermal Insulation = It is a bad Thermal conductor
Dilation and contraction and Fusibility
Contraction: When material gets smaller due to heat
To think about: Why are rails separated by a gap?
Fusibility is the ability of a material to change into a liquid when heated to its melting point.
Examples of melting points
Iron´s melting point...........1535 ºC
Copper´s melting point..........1083 ºC
To think about. Can you speak on the moon?
Write some examples of good and bad conductors
2 Chemical Properties
Oxidation: The change that occurs to most metals when in contact with air or/and water
3 Ecological Properties
Recyclable. Materials that can be reused
Toxic. Materials which are harmful to the environment
Biodegradable. Materials that decompose naturally with time. eg
An apple take about 20 days to decompose
Plastic takes about 100 years
Glass takes about 400 years
http://www.petervaldivia.com/eso/materials-and-wood/videos.php#video1

Exercises 1: Use as many words as you need to describe the following materials:
Properties: Strong, light, weak, heavy, low density, translucent, electrical conductor, magnetic
a) Wood b) Plastic c) Fabric d) Iron e ) Glass f ) Cork g) wool h) Aluminium
Exercise 2: Copy into your notebook the properties of transparent, opaque, waterproof, hard, strong and conductor.
miércoles, 2 de febrero de 2011
Materials and Components
Choosing the correct material for any particular task is essential for a manufacturing activity.
Materials are divided into:
- Raw materials ( natural and artificial ) and
- Processed materials ( artificial materials )
Natural materials
such as wood or stone exist in nature and we use them as they are. Example of these materials are wood, stone, sand, wool etc
Natural resources are split into 3 categories:
•Animal
•Vegetable
•Mineral
Artificial Materials
Artificial materials or Processed materials are those which have been transformed by man.
For example, iron is a natural material because we obtain it from mines. If we add carbon atoms to the iron, we get steel and steel is stronger that iron with better properties.
Even more, if we also add chrome, we get Stainless steel. It is also called corrosion-resistant steel So stainless steel is an artificial material, although we get iron from nature ( natural material
Exercises 1: Copy in your notebook and Complete the following table
natural------------artificial
iron-----------------steel
domingo, 23 de enero de 2011
Materials are divided into:
Raw materials ( natural and artificial ) and
Processed materials ( artificial materials )
Natural materials such as wood or stone exist in nature and we use them as they are. Example of these materials are wood, stone, sand, wool etc
Natural resources are split into 3 categories:
•Animal
•Vegetable
•Mineral
